Maybe try doing the plaits when your hair is wet, and leave them in overnight/for 12 hours, I always find this makes them more wavy than if I do plaits dry.

Or I read recently that another way is to do the plaits, then with heated straighteners, press the plaits in the straighteners all the way down, and the heat should help keep it wavy when you take them out (sorry badly explained!). Haven't tried this one myself but might be worth a try

I do waves using straighteners... takes a tiny bit of practice but I have it down now. You basically twist them one way, then the other way, then back the other way. I'm probably not explaining it well but I'm sure there's a YouTube video somewhere! My hairdresser said its the best way to get waves.

Did you brush your hair after taking the plaits out? Mine just goes bushy if I do that. Running my fingers through it and then spraying salt spray in it seems to keep it properly wavy. Love your hair colour by the way.

GHD is great to create beachy, loose waves. Take small sections of hair and clamp straightener half way down the section, twist 360* then slide GHD down the the end. add a tiny bit of product then bobs your uncle. Trick is to keep sections small.

I luffs waves and have tried EVERYTHING (plopping, ghds, plaits, the whole shebang) but this is what works best for me:

wash hair, quick blow dry just the front section so my parting is how I like it, twist damp hair into a loose twisty bun, leave for several hours (often go to work with it like this), let hair out of bun and scrunch with bumble and bumble texturising stuff or boots curl cream.Then I get lovely waves which last for a couple of days. You have fab hair anyway OP - great colour.

Because it's long and thick, it takes ages to dry so I'll wash and braid it in the evening, then leave the braid in all night and all of the following day and night. That's the result but I probably wash it a lot less than most on here!

I have poker straight hair and have been on a quest for waves for years...straighteners work best for me but if I plan ahead I wash my hair, rough dry til just damp then twist into a few random buns and leave til the evening (you need to be prepared to spend the day looking a bit odd!) Loads of hairspray on when I take it out and it lasts for about 4 hours!